Poultry FCR: How to Calculate Feed Conversion and Find What Went Wrong
A practical guide to calculating FCR, checking whether the number is trustworthy and finding where feed efficiency was really lost.
When feed conversion gets worse, the feed is usually blamed first. Sometimes that is justified. But on a real farm, poor FCR may start somewhere else entirely: feed spilling under the pans, low water flow at the far end of a line, a cold floor during the first three days, subclinical coccidiosis, a processing delay, or simply an incorrect closing feed inventory.
That is why FCR should not be treated as one final number on a production report. It is the outcome of almost everything that happened to the flock—from chick placement to the last feed withdrawal.
Feed conversion ratio (FCR) tells us how much feed was used to produce one unit of output. For broilers, that output is normally live weight. For layers, it is egg mass. A lower FCR generally means better feed efficiency, but only when the calculation is correct and the flocks being compared are genuinely comparable.
This guide explains how to calculate poultry FCR, avoid the most common accounting mistakes and investigate a poor result without automatically assuming that the diet is the only problem.
Field note: A low FCR is not a successful result if the birds are underweight, mortality is high or product quality is poor. Feed efficiency must be read beside body weight, age, livability, uniformity, welfare and financial return.
#The quick answer
For a complete broiler cycle:
FCR = total feed consumed ÷ total live weight produced
If a flock consumes 18,900 kg of feed and produces 12,000 kg of live weight:
18,900 ÷ 12,000 = 1.575 FCRThe flock used 1.575 kg of feed to produce each kilogram of live weight.
For a specific growth period, use weight gain rather than total body weight:
Period FCR = feed consumed during the period ÷ live-weight gain during the same period
The dates must match. Feed recorded from day 15 to day 21 cannot be divided by weight gain measured from day 14 to day 22 and still produce a reliable result.
#What does FCR mean in poultry production?
FCR compares what the birds consumed with what the flock produced. The same unit must be used on both sides of the calculation. Kilograms are most common, but grams or pounds also work if they are used consistently.
An FCR of 1.50 means that 1.50 kg of feed was required for 1 kg of output. An FCR of 1.60 means 1.60 kg was required. The lower figure is more efficient—provided bird age, final weight, genetics, sex, health, season and calculation method are similar.
FCR is useful because it brings many parts of production together. Chick quality, brooding, feed formulation, pellet quality, water, ventilation, stocking density, intestinal health, disease, feed waste and record accuracy can all change the final result.
This is also why FCR cannot diagnose a problem by itself. It tells you that efficiency changed. The flock records and the birds tell you why.
#How to calculate broiler FCR correctly
#Whole-cycle FCR
For a complete broiler cycle, farms commonly use:
FCR = total feed consumed by the flock ÷ total live weight marketedIf the flock is sold in more than one catch, add the live weight from every catch. Do not divide total feed by the weight of the birds remaining after thinning.
Total live weight marketed = weight from first thinning
+ weight from second thinning
+ weight from final catchThe feed figure must cover the same flock from placement until the final feed withdrawal.
#FCR for part of the cycle
When checking FCR for one week or one feed phase, use the gain achieved during that period.
Suppose a flock weighs 10,000 kg at the start of the week and 14,500 kg at the end. It consumes 7,200 kg of feed during the same period.
Live-weight gain = 14,500 − 10,000 = 4,500 kg
Period FCR = 7,200 ÷ 4,500 = 1.60Using the final 14,500 kg as the denominator would incorrectly give an FCR of 0.50 because it includes weight produced before the reporting period.
#Use feed consumed, not feed delivered
One of the most common FCR errors is using feed deliveries as if every kilogram was eaten by the birds.
A practical feed-consumption calculation is:
Feed consumed = opening feed stock
+ feed received
+ feed transferred in
− closing feed stock
− feed transferred outFeed remaining in silos, bins, bags, hoppers and lines at the end of the period must be considered. Spilled or discarded feed has still been purchased, but it did not become bird weight. Record it separately whenever possible; the difference helps distinguish biological inefficiency from physical feed loss.
#Mortality and corrected FCR
Farms do not all handle mortality in the same way. A simple operational FCR often divides feed by the live weight sold. Some companies calculate a technical or mortality-adjusted FCR by estimating the weight of dead and culled birds. Others correct FCR to a standard age or body weight.
None of these methods is automatically wrong, but the method must be stated. Never compare:
actual FCR with corrected FCR;
FCR based on live weight sold with FCR that includes estimated mortality weight;
a company-adjusted figure with a breed objective unless the correction method is identical.
If the calculation changes, the benchmark must change with it.
#How to calculate FCR for laying hens
For layers, egg number alone is not enough. A flock producing many small eggs may look efficient by egg count while producing less saleable egg mass.
Use:
Layer FCR = feed consumed during the period ÷ egg mass produced during the same period
Calculate egg mass as follows:
Egg mass (kg) = number of eggs × average egg weight (g) ÷ 1,000
For example, a flock consumes 8,500 kg of feed and produces 70,000 eggs averaging 62 g.
Egg mass = 70,000 × 62 ÷ 1,000 = 4,340 kg
Layer FCR = 8,500 ÷ 4,340 = 1.96 kg feed/kg egg massLayer businesses may also report grams of feed per egg, feed per dozen eggs or feed per hen housed. These are useful measures, but they are not interchangeable. Label the method and reporting period before comparing flocks.
#What about pullets and breeders?
For pullets, feed conversion can be calculated against body-weight gain, but the lowest number is not the main goal. The flock still needs to reach the target body weight, frame size and uniformity at the correct age.
For broiler breeders, a single FCR can hide more than it reveals. Feed use must be evaluated beside body-weight control, uniformity, egg production, hatchable eggs, fertility, hatchability and chick output. Saving feed while losing uniformity or reproductive performance is not an efficiency gain.
#What is a good FCR for broilers?
There is no universal “good broiler FCR.” The expected value changes with:
genetics and sex;
age and final market weight;
whole-house or separate-sex growing;
feed energy and nutrient density;
mash, crumble or pellet quality;
climate and season;
disease pressure and vaccination program;
stocking density and environmental control;
whether the figure is actual or corrected.
FCR normally increases as broilers become older and heavier. A flock processed at 35 days should not be compared directly with a flock processed at 45 days. Even when both flocks are healthy, the heavier birds use more feed for maintenance and carry each additional kilogram less efficiently.
Use the current performance objectives for the exact genetic line, sex, age and target weight. The useful question is not, “Is 1.55 good?” It is: Did this flock achieve the appropriate target for its own program while maintaining livability, welfare and saleable output?
#The financial cost of a small FCR change
A difference of 0.05 can look minor on a report. Across a commercial flock, it is not.
Suppose a farm produces 125,000 kg of live broiler weight.
Extra feed used = FCR difference × live weight produced
Extra feed used = 0.05 × 125,000
Extra feed used = 6,250 kgMultiply those 6,250 kg by the actual cost per kilogram of feed to see the direct feed-cost difference. This does not yet include the possible effect on days to market, house turnover, processing weight or mortality.
The PoultryRx FCR Calculator can calculate the flock result and add an economic estimate using your own feed cost.
#Before investigating poor FCR, make sure the number is real
Do not change the diet before checking the calculation. Start with the records.
Was the opening feed stock measured or estimated?
Were all deliveries assigned to the correct farm and flock?
Was feed transferred between houses or farms?
Is closing silo stock accurate?
Was feed left in lines or hoppers?
Were all thinning and final catch weights included?
Are bird scales, feed scales and load cells calibrated?
Does the calculation include the same start and end dates for feed and weight?
Is the reported figure actual, mortality-adjusted or weight-corrected?
It is surprisingly common to spend days investigating nutrition before finding that one feed truck, one silo balance or one catch weight was entered incorrectly.
#Read the pattern, not only the final number
The direction of feed and water intake can narrow the investigation.
#FCR rises while feed intake is lower than expected
Check heat stress, insufficient water flow, disease, poor feed palatability, pellet-quality changes and restricted feeder access. Birds cannot convert feed they are not eating, but maintenance requirements continue.
#FCR rises while feed intake is high
Check cold stress, feed spillage, poor nutrient balance, poor digestibility, mycotoxins, abnormal gut passage and inaccurate feed inventory. High intake with weak gain often means the feed is being wasted, poorly used or diverted away from production.
#FCR worsens with wet litter
Inspect drinker pressure and height, leaks, water/feed ratio, minimum ventilation, enteric disease and dietary salt or mineral balance. Wet litter is a clue, not a diagnosis.
#FCR worsens with poor uniformity
Review brooding, crop fill, feeder and drinker distribution, temperature variation, air speed, stocking density and health. The average bird may be on target while a large part of the flock is not.
#FCR deteriorates mainly in the last few days
Some increase is expected as birds become heavier. Also check heat load, processing delays, feed withdrawal errors, high mortality, reduced pellet quality in the finisher and whether the house has reached its practical stocking or ventilation limit.
#The main causes of poor FCR in poultry
#1. A weak start
The first week has a long memory. Delayed placement, low floor temperature, overheating, poor crop fill, uneven chick distribution or restricted water access can reduce early growth. Birds may recover some body weight later, but compensatory growth is rarely free.
Review placement time, chick temperature, floor and litter temperature, crop fill, daily water pattern, seven-day body weight, uniformity and first-week mortality.
#2. The diet does not match the bird or the target
Energy, digestible amino acids, minerals and vitamins must match genetics, age, sex, health and market weight. A formulation can look correct on paper while ingredient variability, poor mixing, oxidation, storage damage, mycotoxins or inaccurate dosing change what reaches the bird.
Work with a qualified poultry nutritionist. Review raw-material quality, formulation, matrix values, mixer performance, sampling, laboratory results and the timing of feed-phase changes.
#3. Feed form and physical losses
Broilers do not eat a formulation spreadsheet; they eat mash, crumbs or pellets. Excessive fines, poor pellet durability, wrong particle size, feed segregation or long empty-feeder periods can affect intake and energy use.
At farm level, inspect pan height, feed depth, line distribution, leaks, augers, bins, rodents and wild-bird access. Feed found in the litter belongs in the FCR investigation.
#4. Water limits feed intake
Water is often checked only after feed intake falls. Low flow at the end of a line, incorrect pressure, blocked nipples, warm water, biofilm or insufficient drinker access can all reduce feed consumption. Leaks create the opposite problem: high apparent water use, wet litter and poorer gut and foot health.
Record the daily water curve, not only the midnight total. Check flow at the far end of lines, pressure, height, flushing, sanitation and the water/feed ratio.
#5. Birds spend feed energy on temperature control
Cold birds use dietary energy to produce heat. Heat-stressed birds reduce intake and spend energy panting. Both situations can worsen FCR through different routes.
Read temperature, relative humidity, air speed, ammonia, carbon dioxide and litter condition together. Sensors are important, but bird distribution, posture and behavior remain essential checks.
Use the PoultryRx Ventilation Advisor to review house and flock requirements, then confirm the recommendation against actual bird response and equipment performance.
#6. Gut health or disease reduces nutrient use
Subclinical coccidiosis, necrotic enteritis, dysbacteriosis, respiratory disease, parasites, immunosuppression and mycotoxins can reduce growth before obvious mortality appears. Small changes in droppings, water intake, litter, uniformity or daily gain may be the first warning.
Use flock history, fresh necropsies, lesion scoring, laboratory testing and veterinary review. Do not add antibiotics or feed additives simply to chase an FCR number without diagnosing the problem.
#7. Stocking density and equipment access become limiting
As the flock grows, the weakest part of the house becomes visible. The floor may still meet a density limit while feeder space, nipple availability, air speed or cooling capacity does not. Competition and uneven environmental conditions reduce uniformity and efficiency.
Recalculate live birds, average weight and kg/m² during the cycle. Check whether every part of the house offers similar access to feed, water and comfortable air.
#8. Processing and feed-withdrawal decisions change the result
A delayed catch adds maintenance feed and increases final live-weight pressure. Excessive feed withdrawal can reduce processing weight, while insufficient withdrawal can leave more gut content and complicate plant results. Thinning weights, final weights and feed cut times must be recorded accurately if FCR is to be interpreted fairly.
#A practical plan to improve FCR
#Step 1: Build one trustworthy data set
Align feed, bird count, mortality, weight, water and dates. Fix obvious inventory or scale errors before changing management.
#Step 2: Compare the flock with the right target
Use the correct genetics, sex, age and weight benchmark. Compare actual FCR with actual FCR, or corrected with corrected.
#Step 3: Protect the first seven days
Preheat properly, verify floor temperature, provide immediate feed and water access, check crop fill and weigh a representative sample at day seven.
#Step 4: Stop physical feed loss
Correct feeder height and depth, repair leaking or damaged equipment, control rodents and measure unexplained differences between received and consumed feed.
#Step 5: Manage water and environment as one system
Review water intake, temperature, humidity, ventilation and litter together. A water problem quickly becomes a feed and litter problem.
#Step 6: Check feed quality from mill to pan
Review formulation, ingredients, mixing, pellet quality, fines, transport, storage and distribution inside the house.
#Step 7: Investigate health changes early
Do not wait for a mortality spike. Falling gain, changing droppings, wet litter, unevenness and altered water/feed ratio justify an early field examination.
#Step 8: Measure the result of one change at a time
When possible, avoid changing feed, ventilation, additives and equipment settings simultaneously. Define what changed, where, when and which daily indicator should respond. Otherwise, even an improvement teaches you very little.
#Common FCR mistakes
Comparing flocks at different ages or market weights without correction.
Using feed delivered instead of feed consumed.
Forgetting feed remaining in silos, bags, hoppers or lines.
Omitting thinning weights or assigning them to the wrong flock.
Comparing actual FCR with a corrected company figure.
Using egg count instead of egg mass for layers.
Judging the result without mortality, body weight and livability.
Reducing nutrient density only to cut feed price per tonne.
Changing several factors at once and losing the ability to identify the cause.
Chasing a low number at the expense of welfare, leg health, egg quality, fertility or saleable output.
#Frequently asked questions
#Is a lower FCR always better?
Usually, but not by itself. A lower FCR is valuable when birds also achieve the required weight, age, livability, uniformity and product quality. An apparently good FCR from underweight birds or incomplete feed records is not a real improvement.
#How can I improve broiler FCR quickly?
First verify feed stock, live weight and catch data. Then look for avoidable losses: feed spillage, poor water flow, wrong feeder settings, temperature stress or a sudden health problem. Nutritional changes should follow a proper review rather than being the automatic first response.
#Why does broiler FCR get worse in hot weather?
Heat stress reduces feed intake, changes bird behavior and uses energy for heat dissipation rather than growth. High humidity, insufficient air speed, warm drinking water and heavy stocking pressure can make the effect worse.
#How should mortality be included in FCR?
Follow one clearly defined company method. Operational FCR may use live weight sold, while technical systems may estimate mortality weight or correct to a standard. State the method and never compare results calculated differently.
#How is layer FCR calculated?
Divide feed consumed by egg mass produced during the same period. Egg mass equals egg number multiplied by average egg weight. State whether other figures, such as feed per dozen or feed per hen housed, are being reported.
#Can feed additives improve FCR?
Some products can support digestion or gut health under the right conditions. Their value depends on the diet, challenge, management and product quality. Correct basic feed, water, environmental and health problems first, then evaluate an additive through a controlled trial and full cost-benefit calculation.
#What is the difference between FCR and EPEF?
FCR measures feed required per unit of output. The European Production Efficiency Factor combines FCR with age, average weight and livability, giving a broader view of broiler performance. Use the PoultryRx EEP Calculator after confirming that the FCR input is accurate.
#Calculate the FCR, then investigate the story behind it
Use the PoultryRx FCR Calculator to enter feed consumed and live weight, compare the result with the correct breed or company target and estimate the feed-cost impact.
Then go back to the flock records. The calculator can confirm the number, but the pattern of feed, water, weight, mortality, temperature and health events explains where the result came from.
Good FCR management is not about finding one magic additive or forcing feed intake down. It is about removing the small losses that accumulate across the cycle—and finding them early enough to act.
#Sources and further reading
Written by
Ahmed Fathi